Outdoor navigation is widely deployed thanks to the development of various global-navigation-satellite-systems (GNSS), e.g., Global Positioning System (GPS), GALILEO, and the like.
Recently, there has been a lot of focus on indoor navigation. This field differs from the outdoor navigation, since the indoor environment does not enable the reception of signals from GNSS satellites. As a result, a lot of effort is being directed towards solving the indoor navigation problem. This problem does not yet have a scalable solution with satisfactory precision.
One solution for indoor navigation includes a Time-of-Flight (ToF) measurement method (also referred to as “Fine Timing Measurement (FTM)”). The ToF may be defined as the overall time a signal propagates from a first station, e.g., a user (“client”) mobile device, to a second station, e.g., an access point (AP), and back to the first station. A range between the first and second stations may be calculated based on the ToF value, for example, by dividing the ToF value by two and multiplying the result by the speed of light.
An estimated location of the first station may be determined by calculating two or more ranges between the first station and two or more other stations, e.g., other APs, by utilizing a suitable method, e.g., a trilateration method.
The accuracy of the estimated location depends on the accuracy of the ToF measurements. There is a need for mechanisms to enable accurate ToF measurements.